Fan switch



Patented Jan. 12, 1943 FAN SWITCH Burton E. Shaw, Bristol, Ind., assignor to Penn Electric Switch 00., Goshen, Ind.,-a corporation of Iowa Application June 10, 1940, Serial No. 339,763

9 Claims. (01. 200-138) My invention relates to a fan switch of the type mounted on a furnace so that a temperature responsive element of the fan switch is subjected to the heat within the plenum chamber thereof.

One object of the invention is to provide a fan switch which incorporates mechanism that is operable to manually close the fan switch so that an air circulating fan controlled by the switch is in continuous operation, as during the summertime, independent of any position that the temperature responsive element may assume.

A further object is to provide the mechanism for manually setting the fan switch for summer operation of comparatively simple and inexpensive construction, whereby it may be attached to the usual type of fan switch without a substantial increase in the cost of manufacture thereof.

More particularly, it is my object to provide a manual control knob on a fan switch casing which, when rotated in one direction, will effect closure of the fan switch regardless of the position of the temperature responsive element, and in another position will permit the temperature responsive element to automatically control the switch.

In the accompanying drawing I have shown a preferred embodiment of my invention showing the fan switch and manual control. The drawing is not intended to be exhaustive and is not to be taken as limiting of the invention, but on the contrary is chosen with a view to illustrating my invention so that others skilled in the art may apply it under varying conditions of practical use and may make such modifications and changes therein as such conditions may make desirable.

In said drawing:

Figure 1 is a front elevation of a fan switch embodying my invention, with the casing thereof shown in section;

Figure 2 is a vertical sectional view as taken on the line 2--2 of Figure 1;

Figure 3 is a front elevation of a manual control knob of the switch;

Figure 4 is a sectional view partially on the line 4-4 of Figure 2, showing the switch open as a result of normal temperature;

Figure 5 is a similar view showing-the switch closed as a result of manual operation of a control knob thereof'to its summer position;

Figure 6 is an enlarged sectional view on the line 6--6 of Figure 4, showing details of the manual control knob and the mechanism which it operates;

Figure '1 is a sectional view on the line 1-1 of Figure 6, showing a notch and projection means of connection between the control knob and a rock shaft, and.

Figure 8 is a diagrammatic side elevation of the switch structure to show a temperature responsive element which normally automatically operates the switch.

0n the accompanying drawing, I have used the reference character C to indicate generally a casing. The casing C has a back plate i0 to which a tube I2 is secured. The front of the casing is completed by a removable cover i3 coacting with fingers l4 at one side and secured by a screw l5 at the other side, as shown in Figure 1.

Within the casing C a bracket B is mounted. on which a switch S is supported. The switch S comprises a casing within which a stationary contact l6 and a movable contact ll are mounted. The contact I! is carried by a spring blade I! which is adapted to be moved by a switch arm IS. The arm is is pivoted on a bracket having V points 20 and carries an armature 2i which coacts with a permanent magnet'22 to provide snap action for the switch. An actuating pin 23 is slidably mounted in the casing of the switch S and operatively connected through a spring 24 with the switch arm I9.

For automatically actuating the pin 23, I provide an actuating arm 25 having perforated ears 26 pivoted on a pin 21. The pin 21 is supported by the bracket B. The arm 25 has a pair of flanges 28 in which a roller 29 is journaled. The roller 29' is adapted to coact with a cam 30 located on a shaft 3|. The shaft 3|, as shown in Figure 8, rotates in response to temperature changes, since it is connected at 32 to one end of a coiled bimetallic element 33. The other end of the element 33 is connected at 34 to the hub i2. The bimetal element 33 is adapted for mounting in a plenum chamber of a furnace, so I that the switch structure is responsive to the temperature therein.

The actuating arm 25 is operatively connected with the actuating pin 23 by a leaf spring 35. I provide a manual control for the switch S consisting of a. lever 36 having a slot 31 receiving the spring 35. The lever 36 has a pair of ears 36 pivoted on the pin 21 and has a lower flange 39 below the pin. A rock shaft 40 is pivoted in the bracket B below the pin 21, and carries a cam lobe 4i coactible at times with the flange 33, as shown in Figure 5. I provide a control knob 42 for the rock shaft 40 which is operativeiy connected thereto as follows: The control knob 42 of the rock shaft 40. The disc 4| is biased toward the bracket B by a spring washer 4!, and a washer ll permanently secured to the rock shaft 4.. The bracket B is provided with a projection ll and the disc 40 is provided with a complementary projection 52. The projections II and 52 are provided by indenting the back of the bracket B and the front of the disc 48. A pair of stop lugs 53 and 54 on the disc 48 coact with the pivot pin 21 to limit rocking motion of the rock shaft 4.. The parts 49, SI and 52 permit movement of the disc 48 from the position of Figure l to the position of Figures 4 and 5, or reversely, with the projection 52 passing over the projection II under the biasing action of the spring washer 4!. After the disc 48 is adjusted to either of said positions. it is retained in the new position due to coaction between the projections II and 52.

Practical operation When the bimetallic element 33 is at approximately room temperature, the parts will assume the position as shown by Figure 4. The lobe of the cam has caused swinging of the actuating lever 25 to the left so that the leaf spring I! has actuated the pin 23 to open the circuit through the switch S. As the temperature of the furnace increases, for instance to 140", as indicated by a pointer 55 and an adjusting scale it, the parts will rotate clockwise from the position of Figure 4, and when the pointer 55 passes an indicating mark 51 on the bracket B the roller "will drop from the lobe of the cam 3| andthe magnet 22 will pull the armature 2| to the position of Figure 5 for closing the switch 8. When the tem perature again recedes to below 140", the switch will be opened. Thus the switch operates automatically in response to temperature changes, which is desirable during the wintertime. During such operation of the switch, the lever 36 will merely float back and forth with the spring II.

When it is desirable to adjust the switch for summer operation (continuous running of the fan), it is merely necessary to rotate the knob 42 counterclockwise, as indicated by S in Figure 3. The parts will then assume the position of Figure 5, wherein the cam 30, being at room temperature, attempts to open the switch 8 but the lever 36, being actuated positively to the position illustrated by the cam 4| of the rock shaft 40, will bow the spring I! toward the right sumciently to permit the switch S to remain in closed circuit position. Whenever it is desirable to again have automatic temperature responsive operation, the knob 42 is rotated clockwise, as indicated by W in Figure 3.

Due to the construction of the knob and rock shaft and the type of connection between them, it is a comparatively simple matter to effect the desired operative connection between them any time that the cover I! is replaced. When placing it in posit on, the disc 45 may engage the ends of the projections 41, as shown by dotted lines in Figure 6, but as soon as the knob 42 is rotated to a position where any of the notches are aligned with the projections 41, the spring 410 will effect axial movement of the stub shaft 43 to the full line operative position. Thereafter,

any further rotation of the knob will effect simultaneous rotation of the rock shaft.

I have provided a comparatively simple means for manually adjusting a fan switch to a positively closed position, regardless of its temperature responsive means which normally actuates the switch. The parts are so constructed and arranged that the switch casing maybe opened for inspection of adjustments at any time desired without interfering with the subsequent proper operation of the manual control for the switch. The mechanism to effect modification of a usual type of fan switch in this manner is comparatively simple and is believed to be fully disclosed in the foregoing specification.

As many changes could be made in the foregoing construction and many apparently widely different embodiments of this invention could be made without departing from the scope thereof, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense. It is also to be understood that the language used in the following claims is intended to cover all of the generic and specific features of the invention herein described and all statements of the scope of the invention which, as a matter of language, might be considered as falling therebetween.

I claim as my invention:

1. In a fan switch, a temperature responsive element for response to the temperature of a furnace plenum chamber, a shaft rotatable thereby in response to temperature changes affecting said temperature responsive element, a cam on said shaft, a switch biased to closed position, an actuating arm therefor coacting with said cam to permit said switch to assume closed position in one position of the cam and to move the switch to open position in another position of the cam, a resilient connection between said actuating arm and said switch, and means to flex said resilient connection to a position for permitting said switch to remain closed, said means comprising a lever which in one position normally permits functioning of said switch through said resilient connection from said cam, a rock shaft for moving said lever from said position to a position preventing such functioning, a casing for said fan switch, and an operating knob rotatable through a wall thereof and operatively connected with said fan switch.

2. In a fan switch, a temperature responsive element, a switch biased to closed position, an actuator therefor coacting with said temperature responsive element to permit said switch to assume closed position in one position of the element and to move the switch to open position in another position of the element, a resilient connection between said actuator and said switch, and means to flex said resilient connection to a position for permitting said switch to remain closed, said means comprising a lever which in one position normally permits functioning of said switch through said resilient connection from said temperature responsive element, and a rock shaft having a projection for moving said lever from said position to a position preventing such functioning independent of the position of said temperature responsive means.

3. In a switch of the character disclosed, a shaft rotated in response to a cam thereon, a switch normally controlled by said cam to assume closed position in one position of the cam and to assume open position in temperature changes,

ating arm for the purpose of actuating the arm another position of the cam, a resilient connection between said cam and said switch, and means to flex said resilient connection to a position effecting a continuous closed circuit position of said switch independent of the position of said cam.

4. In a switch of the character disclosed, a temperature responsive element, a shaft rotatable thereby in response to temperature changes affecting said temperature responsive element, a cam on said shaft, a switch biased to closed position, an actuating arm therefor coacting with said cam to permit said switch to assume closed position in one position of the cam and to move the switch to open position in another position of the cam, a resilient connection between said actuating arm and said switch, and means to flex said resilient connection to a position for permitting said switch to remain closed, said last means comprising a lever which in one position normally permits functioning of said switch from said cam through said resilient connection, a rock shaft for moving said lever from said position to a position preventing such functioning, a casing for said fan switch, and an operating knob rotatable through a wall thereof, said knob having a plural notch and projection means of connection with said rock shaft to permit operative association of the knob with the shaft in different relative positions, said knob being axially movable, and a spring to constrain said knob to a position of coaction between said notch and projection means of connection.

5. In a fan switch, a temperature responsive element, a switch biased to closed position, said temperature responsive element coacting with said switch to permit it to assume closed position in one position of the element and to move the switch to open position in another position of the element, a resilient connection between said element and said switch, and means to flex said resilient connection to a position for permitting said switch to remain closed continuously, said means comprising a lever which in one position normally permits functioning of said switch through said resilient connection, and an operating knob for moving said lever from said position to a position preventing such functioning, said knob having a plurality of notch and projection connections with said lever to permit operative association of the knob with the shaft in different relative positions.

6. In a switch structure of the character disclosed, a casing, a switch therein normally assuming closed position, an actuating pin for said switch operable upon depression to open the switch, an actuating arm pivotally mounted, a spring connection between said actuating arm and said actuating pin for actuating the pin from the arm, a shaft, temperature responsive means for controlling the rotation of said shaft, a cam on said shaft and coacting with said actuin response to temperature changes, a lever coacting with said spring connection to retain it in a position permitting said switch to assume its closed circuit position independent of said cam and temperature responsive means, a rock shaft, a cam lobe thereon engageable with said lever for actuating the same, a knob operatively connected in any one of a plurality of positions of rotation with said rock shaft, said knob being axially movable relative to said casing, and a spring urging said knob toward said rock shaft.

7. In a switch structure of the character disclosed, a switch normally assuming closed position, an actuating pin for said switch operable upon depresslon'to open the switch, an actuator, a spring connection between said actuator and said actuating pin for actuating the pin from the arm, a shaft, temperature responsive means for controlling the rotation of said shaft, a cam on said shaft and coacting with said actuator to actuate the arm in response to temperature changes, a lever coacting with said spring connection to retain it in a position permitting said switch to assume its closed circuit position when said cam is in its open circuit position, a rock shaft, a cam lobe thereon engageable with said lever for actuating the same, and an operating knob for said rock shaft.

8. In a switch structure of the character disclosed, a switch normally assuming closed position, an actuating pin for said switch operable upon depression to open the switch, an actuator, a spring connection between said actuator and said actuating pin for actuating the pin from the actuator, a shaft, temperature responsive means for controlling the rotation of said shaft, a cam on said shaft and coacting with said actuator to actuate it in response to temperature changes, a lever coacting with said spring connection to retain it in a control position permitting said switch to assume its closed circuit posi- -tion when said cam is in its open circuit position,

and manually operable means engageable with said lever for actuating said spring connection to said control position. 1

9. In a switch structure of the character disclosed, a temperature responsive element, a shaft rotatable thereby in response to temperature changes affecting said temperature responsive 

